Implemented cooldown before User is able to resend confirmation code for 2fa

frontend/pshared/lib/models/auth/pending_login.dart

@@ -11,6 +11,8 @@ class PendingLogin {
   final String destination;
   final int ttlSeconds;
   final SessionIdentifier session;
+  final int? cooldownSeconds;
+  final DateTime? cooldownUntil;
 
   const PendingLogin({
     required this.account,
@@ -18,6 +20,8 @@ class PendingLogin {
     required this.destination,
     required this.ttlSeconds,
     required this.session,
+    this.cooldownSeconds,
+    this.cooldownUntil,
   });
 
   factory PendingLogin.fromResponse(
@@ -30,4 +34,30 @@ class PendingLogin {
     ttlSeconds: response.ttlSeconds,
     session: session,
   );
+
+  PendingLogin copyWith({
+    Account? account,
+    TokenData? pendingToken,
+    String? destination,
+    int? ttlSeconds,
+    SessionIdentifier? session,
+    int? cooldownSeconds,
+    DateTime? cooldownUntil,
+    bool clearCooldown = false,
+  }) {
+    return PendingLogin(
+      account: account ?? this.account,
+      pendingToken: pendingToken ?? this.pendingToken,
+      destination: destination ?? this.destination,
+      ttlSeconds: ttlSeconds ?? this.ttlSeconds,
+      session: session ?? this.session,
+      cooldownSeconds: clearCooldown ? null : cooldownSeconds ?? this.cooldownSeconds,
+      cooldownUntil: clearCooldown ? null : cooldownUntil ?? this.cooldownUntil,
+    );
+  }
+
+  int get cooldownRemainingSeconds {
+    final remaining = cooldownUntil?.difference(DateTime.now()).inSeconds ?? 0;
+    return remaining < 0 ? 0 : remaining;
+  }
 }